That's highly unlikely. Proof coins are minted in a process different from regular business strike coins. You see those flat rims on your example? If that were a proof coin the rims would be wire like. Also the fields of the coin would be highly reflective. This would be evident even on an impaired ( a proof coin that's seen circulation) proof.
585,673,899 had been accounted for. Your coin brings it up to the total mintage of 585,673,900. Thank You.